1. Field of the Invention
This invention generally relates to a dynamic damper and a flywheel assembly. More specifically, the present invention relates to a dynamic damper which operates in accordance with an operation of an input shaft of a transmission for dampening a vibration.
2. Background Information
In connection with such a dynamic damper and a flywheel assembly, the assignee has already developed prior arts disclosed in Japanese Laid-Open Patent Publication No. 6-48031 (1994) and others.
In the above prior arts, a second flywheel forming a mass portion is coupled to a drive and transmission system through a torsional damper mechanism to dampen a torsional vibration on the drive and transmission system only when a clutch disk is pressed against a first flywheel. Thereby, an operation impeding shifting of the transmission is suppressed in a disengaged state of a clutch while suppressing gear noises (neutral noises) of the transmission in a neutral state as well as vibrations and noises of the transmission during driving of a vehicle.
In the above prior art, a frictional dampening mechanism (sub-clutch) is used for disengageably coupling the second flywheel to the transmission and drive system. When an operation is performed to couple the second flywheel to the drive and transmission system, a large difference is present between rotation speeds of the second flywheel and the drive and transmission system so that a large load is applied to a portion of the frictional dampening mechanism. Therefore, components of the frictional dampening mechanism must have a sufficient strength, which increases a cost and a size of the frictional dampening mechanism.
In view of the above, there exists a need for dynamic dampers and flywheel assemblies which reduce the forces applied to the components of the sub-clutch to reduce the size and costs of the sub-clutch. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.